Add image upload and vision analysis to Ask Simba chat

Users can now attach images in the web chat for Simba to analyze using
Ollama's gemma3 vision model. Images are stored in Garage (S3-compatible)
and displayed in chat history.

Also fixes aerich migration config by extracting TORTOISE_CONFIG into a
standalone config/db.py module, removing the stale aerich_config.py, and
adding missing MODELS_STATE to migration 3.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

utils/image_process.py

@@ -76,6 +76,39 @@ def describe_simba_image(input):
     return result
 
 
+async def analyze_user_image(file_bytes: bytes) -> str:
+    """Analyze an image uploaded by a user and return a text description.
+
+    Uses Ollama vision model to describe the image contents.
+    Works with JPEG, PNG, WebP bytes (HEIC should be converted before calling).
+    """
+    import tempfile
+
+    # Write to temp file since ollama client expects a file path
+    with tempfile.NamedTemporaryFile(suffix=".jpg", delete=False) as f:
+        f.write(file_bytes)
+        temp_path = f.name
+
+    try:
+        response = client.chat(
+            model="gemma3:4b",
+            messages=[
+                {
+                    "role": "system",
+                    "content": "You are a helpful image analyst. Describe what you see in the image in detail. Be thorough but concise.",
+                },
+                {
+                    "role": "user",
+                    "content": "Please describe this image in detail.",
+                    "images": [temp_path],
+                },
+            ],
+        )
+        return response["message"]["content"]
+    finally:
+        os.remove(temp_path)
+
+
 if __name__ == "__main__":
     args = parser.parse_args()
     if args.filepath: